Vinyl chloride copolymer resin for paste, composition, and process for producing

ABSTRACT

A novel polyvinyl chloride copolymer paste resin comprising a copolymer of a vinyl chloride monomer and a macromonomer of the present invention can be synthesized with high productivity, and can provides a plastisol having high gelation properties, storage stability, superior tensile properties in low-temperature working conditions and heat resistance.

TECHNICAL FIELD

The present invention relates to a novel copolymer of a vinyl chloridemonomer and a macromonomer having a vinyl polymer main chain. Inparticular, it relates to a novel polyvinyl chloride copolymer resin formaking paste (hereinafter referred to as “polyvinyl chloride copolymerpaste resin”) that exhibits superior plastisol gelation properties,plastisol storage stability, tensile properties inlow-temperature-processing conditions, and heat stability, and to amethod for making the same.

BACKGROUND ART

Vinyl chloride resins have excellent mechanical and chemical propertiesand are used for various purposes since they can be formed into rigid ornonrigid products when used with plasticizers.

In particular, a polyvinyl chloride resin for paste applications,hereinafter referred to as the “polyvinyl chloride paste resin”, isgenerally composed of particles having a diameter of 0.1 to 70 μm and isoften used in the form of a plastisol prepared by dispersing the resindried by spray drying or the like into a plasticizer to provideflowability. The plastisol composed of the paste resin can be subjectedto various molding processes such as spread coating, dip coating, rotaryscreen printing, and spray coating, and can be easily formed into anonrigid product by heating after shaping. Accordingly, the plastisolcomposed of the paste resin is widely used for various applications suchas floor covering and wall paper in building materials, underbodycoating and sealer in automotive materials, tarpaulins, and gloves.

A vinyl chloride/vinyl acetate copolymer resin prepared bycopolymerizing vinyl chloride with vinyl acetate has been widely usedfor making products under low-temperature-processing conditions. Whereasthe vinyl chloride/vinyl acetate copolymer resin has superior plastisolgelation properties and superior tensile properties inlow-temperature-processing conditions, storage stability of plastisolsand heat storage stability of the products therefrom are unsatisfactory.

Besides the vinyl chloride/vinyl acetate copolymer resin, the followingmethods using a paste resin for low-temperature-processing have alsobeen suggested.

(1) A polymer blending method, which comprises blending a vinyl chloridepolymer with a vinyl polymer having a low glass transition temperature,can improve the gelation properties of the plastisol. However, thestorage stability and the heat stability are notably poor, and ahomogeneous resin phase is hardly attainable. Thus, the tensileproperties under the low-temperature-processing conditions are oftenpoor.

(2) A method which involves making a copolymer of a vinyl chloridemonomer and a monomer of a vinyl polymer having a low glass transitiontemperature (Japanese Unexamined Patent Application Publication No.63-23947) improves the gelation properties of the plastisol. However,due to the difference among monomers in the polymerization kinetics,homopolymers therefrom tend to be formed. Moreover, the presence of alow molecular weight homopolymer may degrade the properties such as thestorage stability, heat stability, and tensile properties inlow-temperature-processing conditions.

(3) In a method which comprises graft polymerizing a vinyl chloridemonomer onto a vinyl polymer using a cross-linking agent, e.g., apolyfunctional monomer or the like (Japanese Unexamined PatentApplication Publication No. 63-264654), the productivity must besignificantly decreased in order for the cross-linking agent to fullywork. Moreover, an unreacted cross-linking agent degrades the storagestability and heat stability.

In other words, the methods described in paragraphs (1) to (3) canimprove the gelation properties of the plastisol and the tensileproperties of the product under the low-temperature-processingconditions but suffer from problems such as poor storage stability ofthe plastisol and poor heat stability of the product.

A method that uses a pyrolytic organic foaming agent such asazodicarbonamide or oxybis(benzosulfony hydrazide) is commonly used tomake nonrigid polyvinyl chloride foams. Polyvinyl chloride copolymerresins, however, have low melt viscoelasticity around the decompositiontemperature of the foaming agent. Thus, coalescence of cells of thefoams or inability to maintain thickness due to failure in keeping thegenerated gas (permanent set) may result.

On the other hand, it is widely known that graft copolymers withrelatively highly controlled structures and compositions can be madeusing macromonomers.

However, as disclosed in Japanese Unexamined Patent ApplicationPublication No. 4-173818 and U.S. Pat. No. 5,117,151, althoughapplication of such graft copolymers as an additive to a matrix resinsis common, no example that uses a copolymer as the main component ofpaste resins has been reported.

Moreover, as disclosed in Japanese Unexamined Patent ApplicationPublication No. 4-173818, although application of such graft copolymersfrom macromonomers into agents for modifying friction resistance ofnonrigid polyvinyl chloride is known, no example that intentionally usessuch graft copolymer as an additive for accelerating internalplasticization to improve modulus of elasticity and flowability areknown. This is due to the difficulty of stably producing a graftcopolymer from a macromonomer achieving good handling property for thegraft copolymer which has a high compatibility with the polyvinylchloride matrix resin, into which the graft copolymers are addedthereafter.

On the other hand, use of paste resins as additives for rigid/nonrigidpolyvinyl chlorides is widely known. However, the effect of improvingflowability or promoting internal plasticization is small. Liquidplasticizers or different types of polymer may sometimes be added, butthe effect is insufficient if added in small amounts.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a novel polyvinylchloride paste copolymer resin that can be manufactured with highproductivity and that has superior plastisol gelation property,plastisol storage stability, and tensile property in low temperatureprocessing conditions.

Through extensive investigations, the present inventors have found thatthe above-described problems can be solved by using a macromonomer witha controlled molecular distribution and polymer end groups, and havemade the present invention based on the finding.

-   (1) An aspect of the present invention provides a polyvinyl chloride    copolymer resin for paste applications, comprising a copolymer of a    vinyl chloride monomer and a macromonomer having a vinyl polymer    main chain.-   (2) In the above polyvinyl chloride copolymer resin of (1), the    macromonomer having the vinyl polymer main chain may include a    monomer having at least one polymerizable group containing a    polymerizable carbon-carbon double bond at an end thereof.-   (3) In the above polyvinyl chloride copolymer resin of (1) or (2),    the macromonomer having at least one polymerizable, group containing    a polymerizable carbon-carbon double bond at the end, may be    synthesized by radical polymerization.-   (4) In the above polyvinyl chloride copolymer resin of any one    of (1) to (3), the polymerizable group containing the polymerizable    carbon-carbon double bond of the macromonomer may have a structure    represented by the general formula:    —OC (O)C(R)═CH₂    (wherein R represents hydrogen or a C1-C20 organic group).    -   (5) In the above polyvinyl chloride copolymer resin of any one        of (1) to (4), R may represent hydrogen or a methyl group.-   (6) In the above polyvinyl chloride copolymer resin of any one    of (1) to (5), the vinyl polymer main chain of the macromonomer may    be prepared by living radical polymerization.-   (7) In the above polyvinyl chloride copolymer resin of any one    of (1) to (6), the polymer main chain of the macromonomer may be a    (meth)acrylic polymer.-   (8) In the above polyvinyl chloride copolymer resin of any one    of (1) to (7), the polymer main chain of the macromonomer may be a    (meth)acrylic ester polymer.-   (9) In the above polyvinyl chloride copolymer resin of any one    of (1) to (8), wherein the polymer main chain of the macromonomer    may be an acrylic ester polymer.-   (10) In the above polyvinyl chloride copolymer resin of any one    of (1) to (9), the ratio (Mw/Mn) of the weight-average molecular    weight (Mw) to the number-average molecular weight (Mn) of the    macromonomer may be less than 1.8.-   (11) In the above polyvinyl chloride copolymer resin of any one    of (1) to (10), the glass transition temperature of the macromonomer    may be −20° C. or less.-   (12) In the above polyvinyl chloride copolymer resin of any one    of (1) to (11), the copolymer may contain 80 to 99.95 percent by    weight of the vinyl chloride monomer and 20 to 0.05 percent by    weight of the macromonomer.-   (13) Another aspect of the present invention provides a method for    synthesizing the polyvinyl chloride copolymer resin according to one    of above (1) to (12) above, wherein the vinyl chloride monomer is    polymerized with the macromonomer by aqueous polymerization.-   (14) Another aspect of the present invention provides a method for    synthesizing the polyvinyl chloride copolymer resin according to    one (1) to (13) above, wherein the vinyl chloride monomer is    polymerized with the macromonomer by at least one of emulsion    polymerization, suspension polymerization, and microsuspension    polymerization.-   (15) Another aspect of the present invention provides a plastisol    composition exhibiting superior gelation property and high storage    stability, the plastisol composition comprising (A), (B), and (C)    below: (A) 100 parts by weight of a vinyl chloride polymer    containing 20 to 100 percent by weight of the polyvinyl chloride    copolymer resin according to one of claims (1) to (14) and 80 to 0    percent by weight of a vinyl chloride homopolymer resin; (B) 30 to    200 parts by weight of a plasticizer; and (C) 0 to 500 parts by    weight of a filler.-   (16) The plastisol composition of (15) above may further contain 0.1    to 10 parts by weight of a chemical foaming agent, wherein the    plastisol is heated to form uniform micro-cells, whereby the    composition further exhibits excellent foam properties.-   (17) Another aspect of the present invention provides a resin for    canvas and glove applications, prepared by drying an aqueous    dispersion mixture of 20 to 100 percent by weight of the polyvinyl    chloride copolymer resin according to one of (1) to (14) above; and    80 to 0 percent by weight of a vinyl chloride homopolymer resin.-   (18) Another aspect of the present invention provides a polyvinyl    chloride rigid resin composition, comprising 0.1 to 50 percent by    weight of the polyvinyl chloride copolymer resin according to one of    claims (1) to (14); and 99.9 to 50 percent by weight of a vinyl    chloride homopolymer resin, whereby the processability is improved,    and internal plasticization is achieved without a plasticizer.

DESCRIPTION OF THE EMBODIMENTS

The vinyl chloride monomer used in the present invention may be of anytype. For example, the vinyl chloride monomer may be a vinyl chloridemonomer, a vinylidene chloride monomer, or a mixture of these. The vinylchloride monomer may additionally contain at least one monomer that iscopolymerizable with the vinyl chloride monomer and that is preferablyfree of reactive functional groups in the main chain afterpolymerization. Examples of such a monomer include α-olefins such asethylene and propylene and the mixture thereof. When such additionalmonomer is used, the amount of vinyl chloride monomer is preferably atleast 50 percent by weight, and more preferably at least 70 percent byweight.

A macromonomer is a high-molecular weight monomer consisting of monomersof a single type and has at least one polymerizable functional group atone end thereof. The number-average molecular weight of the macromonomermay be any but is preferably in the range of 1,000 to 200,000. Themacromonomer having the vinyl polymer main chain used in the presentinvention is prepared by radical polymerization of monomers, and theresultant macromonomer contains at least one group comprisingpolymerizable carbon-carbon double bond at one end. Examples of thefunctional group include aryl, vinylsilyl, vinyl ether, anddicyclopentadiene. The functional group preferably includes apolymerizable carbon-carbon double bond and is preferably represented bythe general formula:—OC(O)C(R)═CH₂In the formula, R may be any, but is preferably selected from the groupconsisting of —H, —CH₃, —CH₂CH₃, —(CH₂)_(n)CH₃ (n is an integer between2 and 19), —C₆H₅, —CH₂OH, and —CN. More preferably, R is —H or —CH₃.

The vinyl polymer constituting the main chain of the macromonomer usedin the present invention is prepared by radical polymerization. Radicalpolymerization processes can be classified into “ordinary radicalpolymerization” processes and “controlled radical polymerization”processes. In ordinary radical polymerization processes, a monomer witha predetermined functional group is simply copolymerized with a vinylmonomer in the presence of a polymerization initiator. In controlledradical polymerization processes, predetermined functional groups areintroduced into controlled positions, such as ends.

According to the ordinary radical polymerization processes, monomerswith predetermined functional groups are stochastically introduced intothe polymer. A large amount of monomer must thus be fed to prepare ahighly functionalized polymer. Since the process is a type of freeradical polymerization, the molecular weight distribution is wide andthe resulting polymer has high viscosity.

The controlled radical polymerization processes can be furtherclassified into “chain transfer” processes and “living radicalpolymerization” processes. In chain transfer processes, a chain transferagent with a predetermined functional group is used in polymerization tosynthesize a vinyl polymer having a functional group at the end. Inliving radical polymerization processes, the end of propagationcontinues to grow without inducing termination reactions, therebysynthesizing a polymer with a target molecular weight.

Chain transfer processes can synthesize highly functionalized polymersbut require chain transfer agents having particular functional groupswith respect to initiators. Moreover, as in the ordinary radicalpolymerization processes described above, the process is a type of freeradical polymerization; hence, the molecular weight distribution is wideand it is difficult to obtain polymers to have low viscosity.

As disclosed in WO 99/65963, unlike these polymerization processes, aliving radical polymerization process exhibits a high rate ofpolymerization, and a termination reaction rarely occurs althoughradical polymerization in general is difficult to control because ofeasy termination of the reaction resulted from coupling reaction amongradicals. The living radical polymerization process can produce apolymer with a narrow molecular weight distribution, e.g., Mw/Mn ofapproximately 1.1 to 1.5. The molecular weight can be controlled byadjusting the feed ratio between the monomer and the initiator.

Since the living radical polymerization process can produce a polymerwith a narrow molecular distribution and low viscosity, and canintroduce monomers with predetermined functional groups into the targetpositions of the polymer, the process is preferable for synthesizing thevinyl polymer with the predetermined functional group of the presentinvention.

Living radical polymerization processes have been increasinglyinvestigated by various study groups. For example, a process using acobalt porphyrin complex is disclosed in J. Am. Chem. Soc., 1994, vol.116, p. 7943; and a process using a radical scavenger such as anitroxide radical is disclosed in Macromolecules, 1994, vol. 27, p.7288. Moreover, an atom transfer radical polymerization (ATRP) using ahalogenated organic compound or the like as an initiator and atransition metal complex as a catalyst has also been studied.

Among the living radical polymerization processes, an ATRP process forsynthesizing vinyl monomers using a halogenated organic compound, ahalogenated sulfonyl compound, or the like as an initiator and atransition metal complex as a catalyst is particularly preferable forsynthesizing vinyl polymers having predetermined functional groups. Thisis due to the fact that the ATRP process has not only the advantages ofthe living radical polymerization described above, but also highflexibility in designing the initiator or the catalyst since halogen,which contributes significantly to functional group transformation, isat an end. Examples of the ATRP processes are disclosed in Matyjaszewskiet al., J. Am. Chem. Soc. 1995, vol. 117, p. 5614; Macromolecules, 1995,vol. 28, p. 7901; Science, 1996, vol. 272, p. 866; WO 96/30421; WO97/18247; WO 98/01480; WO 98/40415; Sawamoto et al., Macromolecules,1995, vol. 28, p. 1721; Japanese Unexamined Patent ApplicationPublication No. 9-208616; and Japanese Unexamined Patent ApplicationPublication No. 8-41117.

Any of these methods may be employed to synthesize the macromonomer ofthe present invention. Controlled radical polymerization is normallyemployed, and living radical polymerization is preferred for its highcontrollability. The atom transfer radical polymerization is mostpreferred. The monomer that constitutes the main chain of the vinylpolymer of the macromonomer may be of any type. Examples of the monomerinclude (meth)acrylic monomers such as (meth)acrylic acid, methyl(meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl(meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate,tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl(meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate,n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl(meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl(meth)acrylate, toluyl (meth)acrylate, benzyl (meth)acrylate,2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate,2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, stearyl(meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate,γ-(methacryloyloxypropyl)trimethoxysilane, (meth)acrylic acid-ethyleneoxide adducts, trifluoromethylmethyl (meth)acrylate,2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl(meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate,2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate,diperfluoromethylmethyl (meth)acrylate,2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate,2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl(meth)acrylate, and 2-perfluorohexadecylethyl (meth)acrylate; styrenicmonomers such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene,styrenesulfonic acid, and salts thereof; fluorine-containing vinylmonomers such as perfluoroethylene, perfluoropropylene and vinylidenefluoride; silicon-containing vinyl monomers such asvinyltrimethoxysilane and vinyltriethoxysilane; maleic anhydride, maleicacid, and monoalkyl esters and dialkyl esters of maleic acid; fumaricacid, and monoalkyl esters and dialkyl esters of fumaric acid; maleimidemonomers such as maleimide, methylmaleimide, ethylmaleimide,propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide,dodecylmaleimide, stearylmaleimide, phenylmaleimide, andcyclohexylmaleimide; nitrile-containing vinyl monomers such asacrylonitrile and methacrylonitrile; amido-containing vinyl monomerssuch as acrylamide and methacrylamide; vinyl esters such as vinylacetate, vinyl propionate, vinyl pivalate, vinyl benzoate, and vinylcinnamate; alkenes such as ethylene and propylene; conjugated dienessuch as butadiene and isoprene; allyl chloride; and allyl alcohol. Thesemay be used alone or in combination by copolymerization. From theviewpoint of the physical properties of the resultant products, styrenicmonomers and (meth)acrylic monomers are preferable. In particular,acrylic ester monomers and (meth)acrylic ester monomers are preferred,acrylic ester monomer is more preferable, and butyl acrylate is mostpreferable. In the present invention, each of these preferable monomersmay be copolymerized with another monomer or other monomers. In such acase, the content of the preferable monomer is preferably 40 percent byweight.

Ends of vinyl chloride copolymers containing vinyl polymers other thanvinyl chloride polymers synthesized by controlled radicalpolymerization, i.e., other than living radical polymerization, arenever completely copolymerized with the vinyl chloride resin. Thus,stability in the viscosity is rarely achieved due to the presence of theunreacted vinyl polymers contained in the copolymer. Moreover, theunreacted vinyl polymers, which are inhomogeneously distributed in theresin, degrade the physical properties, such as tensile strength, in thelow-temperature-processing conditions. Accordingly, macromonomerssynthesized by living radical polymerization, the ends of which aresubstantially completely copolymerized with the vinyl chloride resin,are preferably used.

The glass transition temperature of the macromonomer is preferably −20°C. or less. When the glass transition temperature exceeds −20° C., theglass transition temperature of the resin cannot be decreasedsufficiently, resulting in insufficient molecular motion, insufficientswelling, and difficulty of introducing a plasticizer under low calorie.As a result, the gelation properties of the plastisol are degraded, andimprovements in sheet properties cannot be expected.

In the present invention, the macromonomer having the vinyl polymer mainchain preferably has such a molecular weight distribution that the ratioof the weight-average molecular weight to the number-average molecularweight is less than 1.8 when measured by gel permeation chromatography(GPC). The ratio is preferably 1.6 or less, and more preferably 1.4 orless. In conducting gel permeation chromatography in the presentinvention, polystyrene gel columns or the like are used with chloroform,tetrahydrofuran, or the like as a mobile phase, and the molecular weightis reported on a polystyrene equivalent. A macromonomer having a vinylpolymer main chain having a wide molecular distribution may suffer fromnonuniform progress of copolymerization reactions with the vinylchloride monomer, and unreacted macromonomers may remain as a result. Inother words, the storage stability of the plastisol may be degraded, andthe strength at break may be decreased.

The number-average molecular weight of the macromonomer having the vinylpolymer main chain of the present invention may be any, but ispreferably 500 to 100,000, more preferably 3,000 to 40,000, and mostpreferably 3,000 to 20,000. At a number-average molecular weight of lessthan 400, the vinyl copolymer does not fully exhibit its potentialcharacteristics. At a number-average molecular weight of more than100,000, handling property is deteriorated, and copolymerization may beinhibited due to insufficient dissolution of the macromonomer into thevinyl chloride monomer.

The polyvinyl chloride copolymer paste resin of the present inventionpreferably contains 80 to 99.95 percent by weight of the vinyl chloridemonomer and 20 to 0.05 percent by weight of the macromonomer. When thecontent of macromonomer is less than 0.05 percent by weight, degradationin tensile properties under low-temperature-processing conditions mayresult. When the content thereof exceeds 20 percent by weight, thepolymerization reaction becomes unstable, thereby resulting in failurein synthesizing the polyvinyl chloride copolymer paste resin of thepresent invention.

The degree of polymerization or the average molecular weight of thepolyvinyl chloride copolymer paste resin of the present invention may beany. When the synthetic resin is a vinyl chloride homopolymer or acopolymer containing vinyl chloride as the main component, the K valuemeasured according to Japanese Industrial Standards (JIS) K 7367-2 ispreferably in the range of 50 to 95, and more preferably 60 to 80.

In the present invention, the polyvinyl chloride copolymer paste resinis preferably synthesized by aqueous polymerization due to its highcontrollability in polymerization. For example, suspensionpolymerization, microsuspension polymerization, or emulsionpolymerization may be employed. In particular, the suspensionpolymerization and the microsuspension polymerization are preferred fromthe viewpoint of particle size control.

The average diameter of the primary particles of the polyvinyl chloridecopolymer paste resin of the present invention is normally 0.1 to 70 μm,and preferably 0.1 to 50 μm. The resin is granulated to increase thebulk density before shipping. The average diameter of the secondaryparticles after granulation is normally 50 to 500 μm.

The polyvinyl chloride copolymer paste resin (primary particles) of thepresent invention may be used alone or in combination with at least onevinyl chloride homopolymer resin. When used alone, the resin preferablyhas a unimodal or multimodal particle size distribution with the mainpeak in the range of 0.1 μm to 10 μm, and more preferably 0.3 to 7 μm,and most preferably 0.1 μm to 10 μm. In order to further enhance theflowability, the polyvinyl chloride copolymer paste resin of the presentinvention that has a particle diameter distribution in the range of 0.1to 10 μm may be mixed with a separately prepared finer polyvinylchloride copolymer paste resin of the present invention having aparticle diameter distribution with the main peak in the range of 0.05to 0.5 μm or with a separately prepared coarser polyvinyl chloridecopolymer paste resin of the present invention having a particlediameter distribution with the main peak in the range of 10 to 70 μm,preferably in the range of 10 to 50 μm.

In order for the plastisol to achieve high flowability, the content ofthe vinyl chloride homopolymer resin can be used together with thepolyvinyl chloride copolymer paste resin of the present inventionpreferably in an amount of 0 to 80 percent by weight, more preferably 0to 50 percent by weight, and most preferably 0 to 30 percent by weight.

When the content of the vinyl chloride homopolymer resin exceeds 80percent by weight, gelation properties is decresed in the uniformity ofgels, resulting in degradation in low-temperature properties and in heatstability (initial coloring time).

For use in canvases and gloves, an aqueous dispersion of polyvinylchloride copolymer paste resin may be blended with an aqueous dispersionof vinyl chloride homopolymer resin, and the resulting blend may bedried for use in canvases and gloves. In such a case, 0 to 80 percent byweight, more preferably 0 to 50 percent by weight and most preferably ofthe vinyl chloride homopolymer resin relative to the polyvinyl chloridecopolymer paste resin is preferably added as the resin solid content,and the mixture is preferably dried before use.

When the content of the vinyl chloride homopolymer resin exceeds 80percent by weight, dried secondary particles in a plastisol state mayeasily return to primary particles, and the plastisol applied to asurface of a cloth (base cloth) may easily permeate toward the backsurface of the cloth resulting in insufficient resin layer, which isundesirable.

Examples of the plasticizer for the plastisol include phthalic esterplasticizers such as di-2-ethylhexyl phthalate(DOP), di-n-octylphthalate (DOP), diisononyl phthalate (DINP), dibutyl phthalate (DBP),and the like; phosphoric ester plasticizers such as tricresyl phosphate(TCP), trixylyl phosphate (TXP), triphenyl phosphate (TPP), and thelike; fatty ester plasticizers such as di-2-ethylhexyl adipate (DEHA),di-2-ethylhexyl sebacate, and the like. These may be used alone or incombination.

The amount of plasticizer is preferably 30 to 200 parts by weightrelative to 100 parts by weight of the vinyl chloride resin containingthe vinyl chloride copolymer resin and the vinyl chloride homopolymerresin. At an amount of less than 30 parts by weight, the plastisol doesnot exhibit sufficient flowability. At a content exceeding 200 parts byweight, the gelation properties may be notably degraded.

Examples of the filler include calcium carbonate, magnesium carbonate,lithium carbonate, kaolin clay, gypsum, mica, talc, magnesium hydroxide,calcium silicate, and borax. Preferably, 0 to 500 parts by weight of thefiller is used relative to 100 parts by weight of the vinyl chlorideresin. Use of more than 500 parts by weight of the filler results in adecrease in flowability and foam properties of the plastisol.

The chemical foaming agent may be any known agent. Examples thereofinclude azodicarbonamide, N,N′-dinitrosopentamethylenetetramine,4,4′-oxybis(benzenesulphonylhydrazide), and hydrazodicarbonamide.

The amount of pyrolytic foaming agent depends on the thickness and theexpansion ratio of the foam. Preferably, 0.1 to 10 parts by weight, andmore preferably 1 to 7 parts by weight of the foaming agent is usedrelative to 100 parts by weight of the vinyl chloride resin. At anamount of less than 1 parts by weight, a sufficient expansion ratiocannot be achieved. At an amount more than 10 parts by weight,undecomposed foaming agent remains, resulting in undesirable colorationor nonuniform foaming, which is undesirable.

The plastisol composition may contain a foam stabilizer (kicker)containing Ba—Zn, Na—Zn, Ba—Ca—Zn, or other metals in addition to theabove-described essential ingredients. The plastisol may additionallycontain one or more known additives such as a vinyl chloride stabilizer,a coloring agent (pigment) such as titanium white, a flame retarder, anantioxidant, an antistatic agent, and processing aids and modifiers.

When the polyvinyl chloride copolymer paste resin is used as aprocessing agent of rigid vinyl chloride and the like, the amount ofpolyvinyl chloride copolymer paste resin is preferably 0.1 to 50 percentby weight, more preferably 1 to 30 percent by weight, and mostpreferably 5 to 20 percent by weight of the rigid vinyl chloride resin.The polyvinyl chloride copolymer paste resin does not significantlyimprove the flowability if the content thereof is less than 0.1 percentby weight. At a content exceeding 50 percent by weight, internalplasticization is accelerated, thereby drastically decreasing themechanical strength and making the resulting resin unsuitable for use ina rigid vinyl chloride product.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional photograph of a sheet of EXAMPLE 9 forevaluating the foaming properties.

FIG. 2 is a cross-sectional photograph of a sheet of EXAMPLE 10 forevaluating the foaming properties.

FIG. 3 is a cross-sectional photograph of a sheet of EXAMPLE 11 forevaluating the foaming properties.

FIG. 4 is a cross-sectional photograph of a sheet of EXAMPLE 12 forevaluating the foaming properties.

FIG. 5 is a cross-sectional photograph of a sheet of COMPARATIVE EXAMPLE7 for evaluating the foaming properties.

FIG. 6 is a cross-sectional photograph of a sheet of COMPARATIVE EXAMPLE8 for evaluating the foaming properties.

FIG. 7 is a cross-sectional photograph of a sheet of COMPARATIVE EXAMPLE9 for evaluating the foaming properties.

FIG. 8 is a cross-sectional photograph of a sheet of COMPARATIVE EXAMPLE10 for evaluating the foaming properties.

FIG. 9 is a cross-sectional photograph of a sheet of COMPARATIVE EXAMPLE11 for evaluating the foaming properties.

BEST MODE FOR CARRYING OUT THE INVENTION EXAMPLES

The present invention will now be described in detail by EXAMPLES.However, the scope of the present invention is not limited to theseexamples. In EXAMPLES, “part(s)” means “part(s) by weight” and “%” means“percent by weight”. <Synthesis of a macromonomer having a vinyl polymermain chain>A macromonomer having a vinyl polymer main chain was preparedas follows.

(Production Example 1)

A 2-L separable flask equipped with a reflux condenser and a stirrer wascharged with CuBr (5.54 g), and the reactor was purged with nitrogen.Acetonitrile (73.8 ml.) was added, and the mixture was stirred for 30minutes in a 70° C. oil bath. Butyl acrylate (132 g), methyl2-bromopropionate (14.4 ml) and pentamethyldiethylenetriamine (4.69 ml)were added to the mixture to initiate the reaction. While heating at 70°C. with stirring, butyl acrylate (528 g) was added dropwise over 90minutes, and the mixture was heated with stirring for 80 minutes.

The reaction mixture was diluted with toluene and was passed through anactivated alumina column. The volatile components were removed bydistillation under a reduced pressure to recover Br-terminated at oneend poly butyl acrylate.

Methanol (800 ml) was fed to a flask and was cooled to 0° C. Thereto,t-butoxy potassium (130 g) was added in a few steps. The reactionmixture was maintained at 0° C., and a methanol solution of acrylic acid(100 g) was added dropwise. Upon completion of the addition, thetemperature of the reaction mixture was brought back to roomtemperature. The volatile components of the reaction mixture wereremoved by distillation under a reduced pressure to recover potassiumacrylate (CH₂═CHCO₂K).

A 500-mL flask with a reflux condenser was charged with the resultantBr-terminated at one end poly butyl acrylate (150 g), potassium acrylate(7.45 g), and dimethylacetoamide (150 ml). The mixture was heated at 70°C. with stirring for 3 hours. Dimethylacetoamide was distilled away fromthe reaction mixture, and the resulting mixture was dissolved in tolueneand was passed through an activated alumina column. Toluene was removedby distillation to recover an acryloyl-terminated at one end poly butylacrylate macromonomer. The number-average molecular weight was 6,000,and the molecular weight distribution was 1.14.

(Production Example 2)

An acryloyl-terminated at one end poly butyl acrylate macromonomerhaving a number-average molecular weight of 12,000 and a molecularweight distribution of 1.11 was synthesized as in PRODUCTION EXAMPLE 1but with 7.2 ml of methyl 2-bromopropionate.

(Production Example 3)

An acryloyl-terminated at one end poly-2-ethylhexyl acrylatemacromonomer having a number-average molecular weight of 12,000 and amolecular weight distribution of 1.15 was synthesized as in PRODUCTIONEXAMPLE 1 except that 2-ethylhexyl acrylate was used instead of butylacrylate.

(Production Example 4)

An acryloyl-terminated at one end poly n-octyl acrylate macromonomerhaving a number-average molecular weight of 12,000 and a molecularweight distribution of 1.10 was synthesized as in PRODUCTION EXAMPLE 1except that n-octyl acrylate was used instead of butyl acrylate.

(Example 1)

<Polymerization>

A polyvinyl chloride copolymer paste resin of the present invention,i.e., a vinyl chloride/at one end poly butyl acrylate graft copolymerpaste resin in particular, was synthesized as follows.

Into a fully deaerated, N₂-purged 15-L pressure container, were placedthe acryloyl-terminated poly butyl acrylate (70 g) of PRODUCTION EXAMPLE1, a vinyl chloride monomer (2.23 kg), α,α′-azobis-2,4-dimethylvaleronitrile (1.6 g), and stearyl alcohol (32.2g). The mixture was homogenized for 2 minutes. An aqueous sodium laurylsulfate (26.8 g) solution (6.9 kg) was added to the container, and themixture was homogenized again for 3 minutes to give a monomer-dispersedliquid. The monomer-dispersed liquid was transferred to a 5-L reactionvessel. The inside of the vessel was kept at 50° C. to initiatepolymerization. After approximately 6 hours, the pressure inside thevessel started to decrease. The monomers in the polymerization vesselwere recovered, and the inside of the vessel was cooled. Subsequently,the latex was recovered. The conversion rate of the vinyl chloridemonomers was approximately 90%. The latex was dried with a spray drier(inlet: 110° C., outlet: 50° C.) to prepare a powder of the vinylchloride/polybutyl acrylate graft copolymer resin.

A plastisol was prepared from the resin. A tensile test and sheet heatresistance evaluation were conducted using this resin. The results areshown in Table 1.

(EXAMPLE 2)

A resin was prepared as in EXAMPLE 1 but with 140 g ofacryloyl-terminated at one end poly butyl acrylate of PRODUCTION EXAMPLE1 and 2.16 kg of the vinyl chloride monomer. A plastisol was preparedfrom the resin, and a tensile test and sheet heat resistance evaluationwere conducted as in EXAMPLE 1. The results are shown in Table 1.

(Example 3)

A resin was prepared as in EXAMPLE 1 except that the macromonomer ofPRODUCTION EXAMPLE 2 was used instead of the acryloyl-terminated at oneend poly butyl acrylate macromonomer. A plastisol was prepared from theresin, and a tensile test and sheet heat resistance evaluation wereconducted as in EXAMPLE 1. The results are shown in Table 1.

(Example 4)

A resin was prepared as in EXAMPLE 1 but with 230 g ofacryloyl-terminated at one end poly butyl acrylate of PRODUCTION EXAMPLE1 and 2.07 kg of the vinyl chloride monomer. A plastisol was preparedfrom the resin, and a tensile test and sheet heat resistance evaluationwere conducted as in EXAMPLE 1. The results are shown in Table 1.

(Example 5)

A resin was prepared as in EXAMPLE 1 but with 23 g ofacryloyl-terminated at one end poly butyl acrylate of PRODUCTION EXAMPLE1 and 2.28 kg of the vinyl chloride monomer. A plastisol was preparedfrom the resin, and a tensile test and sheet heat resistance evaluationwere conducted as in EXAMPLE 1. The results are shown in Table 1.

(Example 6)

A resin was prepared as in EXAMPLE 1 but with 460 g ofacryloyl-terminated at one end poly butyl acrylate of PRODUCTION EXAMPLE1 and 1.84 kg of the vinyl chloride monomer. A plastisol was preparedfrom the resin, and a tensile test and sheet heat resistance evaluationwere conducted as in EXAMPLE 1. The results are shown in Table 1.

(Example 7)

A resin was prepared as in EXAMPLE 1 except that the macromonomer ofPRODUCTION EXAMPLE 3 was used instead of the acryloyl-terminated at oneend poly butyl acrylate of PRODUCTION EXAMPLE 1. A plastisol wasprepared from the resin, and a tensile test and sheet heat resistanceevaluation were conducted as in EXAMPLE 1. The results are shown inTable 1.

(Example 8)

A resin was prepared as in EXAMPLE 1 except that the macromonomer ofPRODUCTION EXAMPLE 4 was used instead of the acryloyl-terminated at oneend poly butyl acrylate of PRODUCTION EXAMPLE 1. A plastisol wasprepared from the resin, and a tensile test and sheet heat resistanceevaluation were conducted as in EXAMPLE 1. The results are shown inTable 1.

(Example 9)

<Polymerization>

Into a fully deaerated, N₂-purged 20-L pressure container, were placedthe acryloyl-terminated at one end poly butyl acrylate (820 g) ofPRODUCTION EXAMPLE 1, a vinyl chloride monomer (7.43 kg),di(2-methylhexyl) peroxydicarbonate (4 g), 3,5,5-trimethylhexanoylperoxide (2.1 g), partly saponified polyvinyl alcohol (28.8 g of partlysaponified polyvinyl alcohol having a saponification value of 87 to 89mol % and a degree of polymerization of 3,500; 1.4 g of partlysaponified polyvinyl alcohol having a saponification value of 76.5 to 90mol % and a degree of polymerization of 900), methyl cellulose(molecular weight: 30,000, 1.7 g), butyl stearate (48.5 g), and 16.5 kgof water. The mixture was stirred while the inside of the container waskept at 54° C. to initiate polymerization. After approximately 6 hours,the pressure inside the container started to decrease. The monomers inthe polymerization container were recovered, and the inside of thevessel was cooled. Subsequently, the latex was recovered. The conversionrate of the vinyl chloride monomers was approximately 90%. Aftercentrifugal drying, the latex was subjected to fluidized drying at 60°C. to prepare a vinyl chloride/poly butyl acrylate graft copolymerresin.

A vinyl chloride resin was prepared by powder-blending 70 parts of aknown vinyl chloride paste resin (PSM-30; Kaneka Corporation, vinylchloride homopolymer, K-value: 72) with 30 parts of the resultant resin.The foam properties thereof were evaluated. The results are shown inTable 3.

(Example 10)

A vinyl chloride resin was prepared by powder-blending 40 parts of aknown vinyl chloride paste resin (PSM-30; Kaneka Corporation, vinylchloride homopolymer, K-value: 72) with 30 parts of the vinylchloride/poly butyl acrylate graft copolymer resin of EXAMPLE 4 and 30parts of a known vinyl chloride blend resin (PBM-B5F; KanekaCorporation, vinyl chloride homopolymer, K-value: 68). The foamproperties thereof were evaluated. The results are shown in Table 3.

(Example 11)

A vinyl chloride/poly butyl acrylate graft copolymer resin was preparedas in EXAMPLE 9 but with 250 g of the acryloyl-terminated at one endpoly butyl acrylate and 8 kg of the vinyl chloride monomer.

A vinyl chloride resin was prepared by powder-blending 70 parts of aknown vinyl chloride paste resin (PSM-30; Kaneka Corporation, vinylchloride homopolymer, K-value: 72) with 30 parts of the above graftcopolymer resin. The foam properties thereof were evaluated. The resultsare shown in Table 3.

(Example 12)

The polymer resin of EXAMPLE 4 was used to evaluate the foam properties.The results are shown in Table 3.

(Example 13)

A resin prepared by drying the polymer resin latex of EXAMPLE 4 with aspray dryer (inlet: 150° C., outlet: 60° C.) was prepared to investigatecloth permeability. The results are shown in Table 4.

(Example 14)

A latex blend containing 60 percent by weight of the polymer resin latexof EXAMPLE 4 on a dry basis and 40 percent by weight of a known vinylchloride latex (PSM-30; Kaneka corporation, vinyl chloride homopolymer,K value: 72) for pastemaking was prepared. The blend was spray-dried(inlet: 150° C., outlet: 60° C.) to prepare a dry resin, and a clothpermeability test was conducted. The results are shown in Table 4.

(Example 15)

A latex blend containing 30 percent by weight of the polymer resin latexof EXAMPLE 4 on a dry resin basis and 70 percent by weight of a knownvinyl chloride latex (PSM-30; Kaneka corporation, vinyl chloridehomopolymer, K value: 72) for pastemaking was prepared. The blend wasspray-dried (inlet: 150° C., outlet: 60° C.) to prepare a dry resin, anda cloth permeability test was conducted. The results are shown in Table4.

(Example 16)

A mixture prepared by powder blending 95 parts of a common rigid vinylchloride resin (S1001; Kaneka Corporation, vinyl chloride homopolymer, Kvalue: 68) and 5 parts of the copolymer of EXAMPLE 4. The mixture waspressed with rolls into a sheet. The tensile/flowability of the rigidmixture was examined. The results are shown in Table 5.

(Example 17)

A mixture prepared by powder-blending 80 parts of a common rigid vinylchloride resin and 20 parts of the copolymer of EXAMPLE 4. The mixturewas pressed with rolls into a sheet. The tensile/flowability of therigid mixture was examined. The results are shown in Table 5.

(Comparative Example 1)

A resin was prepared as in EXAMPLE 1 but without usingacryloyl-terminated at one end poly butyl acrylate. The vinyl chloridemonomer content was changed to 2.30 kg. A plastisol was prepared fromthe resin, and a tensile test and sheet heat resistance evaluation wereconducted. The results are shown in Table 2.

The sheet strength at break at 140° C. was low, and the heat resistancewas poor.

(Comparative Example 2)

A resin was prepared as in EXAMPLE 1, but with a vinyl acetate monomerinstead of the acryloyl-terminated at one end poly butyl acrylate. Inparticular, the vinyl acetate monomer (70 g) was used with the vinylchloride monomer (2.23 kg). A plastisol was prepared from the resin, anda tensile test and sheet heat resistance evaluation were conducted. Theresults are shown in Table 2.

The heat resistance was poor.

(Comparative Example 3)

A resin was prepared as in EXAMPLE 1, but with a vinyl acetate monomerinstead of the acryloyl-terminated at one end poly butyl acrylate in anamount twice that of the acryloyl-terminated poly butyl acrylate. Inparticular, the vinyl acetate monomer (140 g) was used with the vinylchloride monomer (2.16 kg). A plastisol was prepared from the resin, anda tensile test and sheet heat resistance evaluation were conducted. Theresults are shown in Table 2.

The viscosity was excessively high. The stability and the heatresistance were poor.

(Comparative Example 4)

A resin was prepared as in EXAMPLE 1, but with a butyl acrylate monomerinstead of the acryloyl-terminated at one end poly butyl acrylate. Inparticular, the butyl acrylate monomer (70 g) was used with the vinylchloride monomer (2.23 kg). A plastisol was prepared from the resin, anda tensile test and sheet heat resistance evaluation were conducted. Theresults are shown in Table 2. The heat resistance was poor.

(Comparative Example 5)

A resin was prepared as in EXAMPLE 1, but with a methylmethacrylate/butyl methacrylate/styrene copolymer resin instead of theacryloyl-terminated at one end poly butyl acrylate. In particular, themethyl methacrylate/butyl methacrylate/styrene copolymer resin (230 g)was used with the vinyl chloride monomer (2.07 kg). A plastisol wasprepared from the resin, and a tensile test and sheet heat resistanceevaluation were conducted. The results are shown in Table 2.

The viscosity was excessively high. Stable storage in the plastisol formwas impossible. The tensile strength at low temperature was poor.

(Comparative Example 6)

A resin was prepared by blending the vinyl chloride resin of COMPARATIVEEXAMPLE 1 with 6 parts of a solution prepared by dissolving poly t-butylacrylate having Mn=40,000 in toluene (poly t-butylacrylate/toluene=30%/70%). A plastisol was prepared from the resin, anda tensile test and sheet heat resistance evaluation were conducted. Theresults are shown in Table 2. The tensile strength at low temperaturewas low.

(Comparative Example 7)

The polymer resin of COMPARATIVE 1 was used to evaluate the foamproperties. The results are shown in Table 3. The sol viscosity washigh, and scale wrinkles resulting from flattening during re-heatingoccurred.

(Comparative Example 8)

The foam properties were evaluated using 70 parts of a known vinylchloride resin used for paste making (PSM-30; Kaneka Corporation, vinylchloride homopolymer, K value: 72)) and 30 parts of a known vinylchloride resin used for blending (PBM-B5F, Kaneka Corporation, vinylchloride homopolymer, K value: 68). The results are shown in Table 3.The state of cells was poor, and scale wrinkles resulting fromre-heating occurred.

(Comparative Example 9)

The foam properties were evaluated using the polymer resin ofCOMPARATIVE EXAMPLE 3. The results are shown in Table 3. The viscositywas high, the expansion ratio was low, and permanent set occurred duringre-heating.

(Comparative Example 10)

The foam properties were evaluated using the polymer resin ofCOMPARATIVE EXAMPLE 4. The results are shown in Table 3. The viscositywas high, the expansion ratio was low, and permanent set occurred duringre-heating.

(Comparative Example 11)

A mixture of 100 parts of the polymer resin of COMPARATIVE EXAMPLE 1 and9 parts of a toluene solution (polymer concentration: 30%) of a polyt-butyl acrylate (Mn=40,000) was used to evaluate the foam properties.The results are shown in Table 3. A significantly large amount of scalewrinkles occurred.

(Comparative Example 12)

The polymer resin latex of COMPARATIVE EXAMPLE 1 was dried in a spraydryer (inlet: 150° C., outlet: 60° C.), and the cloth permeability wasevaluated. The results are shown in Table 4. The gel permeability andthe permeability at room temperature were notably poor.

(Comparative Example 13)

The polymer resin latex of COMPARATIVE EXAMPLE 3 was dried in a spraydryer (inlet: 150° C., outlet: 60° C.), and the cloth permeability wasevaluated using the dried resin. The results are shown in Table 4. Thegel permeability and the permeability at room temperature were notablypoor.

(Comparative Example 14)

A mixture was prepared by powder-blending 60 parts of the polymer resinof EXAMPLE 13 and 40 parts a known vinyl chloride resin used for pastemaking (PSM-30, Kaneka Corporation, vinyl chloride homopolymer, K value:72). The cloth permeability was evaluated. The results are shown inTable 4.

The gel permeability and the permeability at room temperature werenotably poor.

(Comparative Example 15)

A common rigid vinyl chloride resin (S1001; Kaneka Corporation, vinylchloride homopolymer, K value: 68) alone was pressed with rolls into asheet. The tensile/flowability of a rigid mixture containing this resinwas examined. The results are shown in Table 5.

The modulus of elasticity did not decrease sufficiently, and the flowvalue was low. No plasticizing effect was achieved.

(Comparative Example 16)

A rigid vinyl chloride copolymer resin (TAE200, Mitsui Chemicals, Inc.,contains 7% butyl acrylate) alone was pressed with rolls into a sheet.The tensile/flowability of a rigid mixture containing this resin wasexamined. The results are shown in Table 5.

The flow value was low, i.e., flowability was poor.

(Comparative Example 17)

A mixture prepared by powder blending 95 parts of a known rigid vinylchloride resin (S1001; Kaneka Corporation, vinyl chloride homopolymer, Kvalue: 68) and 5 parts of DOP. The mixture was pressed with rolls into asheet. The tensile/flowability of a rigid mixture containing this resinwas examined. The results are shown in Table 5.

Antiplasticization occurred, the modulus of elasticity was high, and theelongation was low.

(Comparative Example 18)

A mixture prepared by blending 90 parts of a known rigid vinyl chlorideresin (S1001; Kaneka Corporation, vinyl chloride homopolymer, K value:68) and 5 parts of DOP. The mixture was pressed with rolls into a sheet.The tensile/flowability of a rigid mixture containing this resin wasexamined. The results are shown in Table 5.

Antiplasticization occurred, the modulus of elasticity was high, and theelongation was low.

<Method for Making the Plastisol and Evaluation of the Plastisol>

A resin was prepared by mixing each of the vinyl chloride resins ofEXAMPLES 1 to 8 and COMPARATIVE EXAMPLES 1 to 5 (100 parts) with aplasticizer (di-n-octyl phthalate (DOP): 70 parts) and a stabilizer(AC-311, Asahi Denka Co., Ltd.: 3 parts) using an Ishikawa kneader for10 minutes. The mixture was defoamed under a reduced pressure to preparethe plastisol.

While the resultant plastisol was kept in a 40° C. thermostat, theviscosities after one hour and after 24 hours were measured using aBrookfield viscometer (Type BM, manufactured by Tokyo Seiki Co., Ltd.)with a number 4 rotor at a rotor speed of 6 rpm. The ratio of viscosityincrease, i.e., “viscosity after 24 hours/viscosity after 1 hour”, wascalculated. The lower the ratio of the viscosity increase, the longerthe pot life and higher the long-term stability.

<Evaluation of Tensile Properties>

The plastisol was applied on a glass plate to a thickness ofapproximately 200 μm and was heated in an oven (120° C. or 140° C., 10min) to prepare a sheet. The sheet was cut into a JIS dumbbell No. 3specimen, and the specimen was subjected to a tensile test at 100 mm/minusing an autograph (AGS-100A, manufactured by Shimadzu Corporation) toexamine the tensile strength at break (TSb).

If sufficiently high strength is exhibited in a 120 to 140° C.temperature range, which is lower than typical shaping conditions forvinyl chloride, processing under low-temperature shaping conditionsbecomes possible, which is preferable.

<Evaluation of the Sheet Heat Resistance>

The plastisol was applied on a glass plate to a thickness ofapproximately 200 μm and was heated in an oven (140° C., 10 min) toprepare a sheet. The sheet was placed on a glass plate and heated againin an oven (140° C.). The sheet was removed from the oven every minuteto determine the initial coloring (blackening) time of the sheet. Whenthe time taken for the sheet to undergo initial coloring (hereinafter,referred to as the “initial coloring time”) is long, the sheet suffersless from coloring and a decrease in strength due to thermal degradationof the resin.

<Evaluation of Foam Properties>

The plastisol was prepared by mixing 100 parts of each of the vinylchloride resins of EXAMPLES 9 to 12 and COMPARATIVE EXAMPLES 7 to 9, 48parts of a plasticizer (DOP), 1 part of epoxidized vegetable oil(O-130P, Asahi Denka Co., Ltd.), 1.5 parts of zinc oxide, 2.4 parts ofADCA (AC-3C #K2, Eiwa Chemical Ind. Co., Ltd.), 8 parts of titaniumoxide (JR-600A, Tayca Corporation), 40 parts of calcium carbonate(Whiton-H, Shiraishi Calcium Co., Ltd.), and 2 parts of a viscocityreducing agent (Shellsol S, Shell Chemicals Japan) with a dissolver (for3 min at 1,000 rpm). The plastisol was applied on a plain paper (KishuPaper Co., Ltd.) to a thickness of approximately 300 μm. The paper waspassed through an infrared oven (furnace temperature: 140° C., time:approximately 20 sec) to prepare a semicured stock.

The semicured stock was cut to 30 cm by 15 cm. The cut semicured stockwas placed in a hot-air oven (PHH-100, Tabai Espec Corporation) heatedto 220° C. and was removed from the oven after 50 seconds to prepare afoam.

The expansion ratio of the foam was calculated by determining the foam,and the rate of the closed cells in the foam was measured with an airpycnometer (manufactured by Beckman Instruments Inc.).

The fineness and uniformity of the cells were visually observed from across-section of the foam.

Furthermore, the foam was heated again in an infrared oven (furnacetemperature: 160° C., time: approximately 15 sec), and was pressed withan embossing roller immediately after the heating so as to visuallyobserve the degree of flattening of the foam.

The flattening is a phenomenon in which scale wrinkles are produced onsurfaces of the foam caused by successive flattening of the cells due toembossing. The state of flattening was evaluated by visual observation.

The expansion ratio of the foam is preferably high and the cells arepreferably dense and uniform so that degradation in quality, i.e., adecrease in expansion ratio resulting from secondary processing(re-heating) of the foam and a decrease in the embossability (patternreproducibility) can be prevented.

The visual observation of the cross-section of the foam was made usingElectroMicroscope equipped with CCD camera [PRODUCT of Keyence Co.,Ltd:VH-6200].

<Evaluation of Cloth Permeability>

The plastisol was prepared by mixing 100 parts of each of the vinylchloride resins of EXAMPLES 13 to 15 and COMPARATIVE EXAMPLES 10 to 12,120 parts of a plasticizer (DOP), and 3 parts of a stabilizer (AC-311,Asahi Denka Co., Ltd.) using an Ishikawa kneader for 10 minutes. Theresulting mixture was defoamed under a reduced pressure to prepare theplastisol.

Approximately 3 g of the plastisol was placed on a knit fabric and thestate of permeation of the plastisol on still standing was observed overtime.

On the other hand, approximately 3 g of the plastisol was placed on aknit fabric and was immediately placed in a hot-air oven (PHH-100,manufactured by Tabai Corporation) heated to 180° C. to gelate theplastisol. The state of the plastisol permeating into the fabric duringheating was observed. The gelated product was scratched with nails tocomparatively examine the peeling ease.

A gelated product showing less permeation into the fabric and higherpeeling ease is suitable for use in canvases and gloves since it feelsgood to the touch and has high strength.

<Evaluation of Tensile/Flowability of a Rigid Mixture>

A mixture was prepared by kneading 100 parts of the resin, 1.5 parts ofa stabilizer (#8831, Nitto Kasei Co., Ltd.), and 0.5 part of a higheralcohol (CA-86; Kao Corporation). The mixture was rolled (185° C., 5min) and pressed (190° C., 10 min) to prepare a pressed sheetapproximately 1 mm in thickness. The sheet was cut into a dumbbellpiece, and a tensile test was performed with an autograph at 100 mm/min.

A method B flow test (load: 100 kg) was performed on a pulverizedpressed sheet. In the tensile test, the modulus of elasticity ispreferably low and the elongation at break is preferably high tofacilitate the internal plasticization of the resin. The method B flowis preferably high since flowability during working can be improved.TABLE 1 EXAMPLE 1 EXAMPLE 2 EXAMPLE 3 EXAMPLE 4 EXAMPLE 5 EXAMPLE 6EXAMPLE 7 EXAMPLE 8 Acryloyl- Vinyl chloride/poly(ester acrylate) graftcopolymer resin terminated PRO- PRO- PRO- PRO- PRO- PRO- PRO- PRO-poly(ester DUCTION DUCTION DUCTION DUCTION DUCTION DUCTION DUCTIONDUCTION acrylate) EXAMPLE 1 EXAMPLE 1 EXAMPLE 2 EXAMPLE 1 EXAMPLE 1EXAMPLE 1 EXAMPLE 3 EXAMPLE 4 Molecular 6,000 6,000 12,000 6,000 6,0006,000 12,000 12,000 weight Compounding 97/3 94/6 97/3 90/10 99/1 80/2097/3 97/3 ratio Rate of 20% 80% 40% 120% 40% 230% 25% 35% viscosityincrease Tensile test: 3.2 MPa 3.3 MPa 2.5 MPa 3.8 MPa 2.7 MPa 4.1 MPa3.3 MPa 3.5 MPa 120° C. Tensile test: 6.4 MPa 6.6 MPa 6.0 MPa 7.9 MPa4.6 MPa 8.2 MPa 7.5 MPa 7.8 MPa 140° C. Initial coloring 9 min 9 min 9min 9 min 8 min 10 min 9 min 9 min (heat resistance)

TABLE 2 COMPARATIVE COMPARATIVE COMPARATIVE EXAMPLE 5 COMPARATIVEEXAMPLE 2 EXAMPLE 3 COMPARATIVE Polymer blend EXAMPLE 6 COMPARATIVEVinyl chloride/vinyl Vinyl chloride/vinyl EXAMPLE 4 of Vinyl chlorideresin Mixture of vinyl EXAMPLE 1 acetate copolymer acetate copolymerButyl acrylate and MMA/BMA/St chloride resin Vinyl chloride resin resinresin copolymer resin copolymer resin and poly butyl acrylateCompounding 100 97/3 94/6 97/3 90/10 98/2 ratio Ratio of viscosity 50%100% 1620% 70% Undetectable 50% increase excessively high gelatedviscosity Tensile test: 2.4 MPa 3.5 MPa 6.7 MPa 2.7 MPa 1.4 MPa 1.9 MPa120° C. Tensile test: 4.1 MPa 8.8 MPa 8.9 MPa 5.2 MPa 2.0 MPa 3.2 MPa140° C. Initial coloring 6 min 5 min 5 min 4 min 6 min 7 min (heatresistance)*In COMPARATIVE EXAMPLE 5, the compound ratio of MMA/BMA/St = 38/23/39,Mn = 200,000.*In COMPARATIVE EXAMPLE 6, poly butyl acrylate had Mn = 40,000.*Ratio of viscosity increase = (viscosity after 24 hours/viscosity after1 hour); plastisol maintained at 40° C.

TABLE 3 Ex. 9 Ex. 10 Ex. 11 Ex. 12 C. Ex. 7 C. Ex. 8 C. Ex. 9 C. Ex. 10C. Ex. 11 Paste resin PSM-30: 70 PSM-30: 40 PSM-30: 70 Ex. 4: 100 C. Ex.1 PSM-30: 70 C. Ex. 3 C. Ex. 4 C. Ex. 1: 100 Ex. 4: 30 p-BA Blend resin10% BA PBM-B5F: 30 3% BA PBM-B5F: 30 addition: 2.7 macromonomermacromonomer graft copolymer: graft copolymer: 30 30 Sol viscosity 6.87.5 5.6 10.0 12.3 7.0 25.0 27.0 12.3 Pa · s Pa · s Pa · s Pa · s Pa · sPa · s Pa · s Pa · s Pa · s Expansion 5.3 5.6 5.1 5.6 5.6 5.2 3.2 3.45.5 ratio Rate of 27% 35% 17% 42% 35% 25% 0% 0% 35% closed cellEvaluation of B A B A B C D D A cells (flattened) (flattened) Sectionphotograph of foam Flattening A A A A B B — (flat) — (flat) C*Ex.: EXAMPLE, C. Ex: COMPARATIVE EXAMPLE*Evaluation of cells: A: small and uniform; B: large but uniform; C:small but nonuniform; D: large and nonuniform*Evaluation of flattening: A: no scale wrinkles; B: small scalewrinkles; C: large scale wrinkles.

TABLE 4 COMPARATIVE COMPARATIVE COMPARATIVE EXAMPLE 14 EXAMPLE 15EXAMPLE 12 EXAMPLE 13 EXAMPLE 14 EXAMPLE 13 EXAMPLE 4: 60 EXAMPLE 4: 30COMPARATIVE COMPARATIVE EXAMPLE 13: 60 EXAMPLE 4 PSM-30: 40 PSM-30: 70EXAMPLE 1 EXAMPLE 3 PSM-30: 40 Mixing conditions Latex blend Powderblend Gel permeability A A A C C C Adhesiveness A A A UndetectableUndetectable Undetectable Still standing A A A C C C after 5 min StillStanding A A B C C C after 60 minPermeability: A: no permeation to back of cloth, B: slight bleeding ofplasticizer, C: permeation of sol found on back of clothAdhesiveness: A: gel product tightly adhered on cloth, B: some gelproduct detached by scratching, C: whole gel product easily separated byscratching

TABLE 5 COM- COM- COM- COM- PARATIVE PARATIVE PARATIVE PARATIVE EXAMPLE16 EXAMPLE 17 EXAMPLE 15 EXAMPLE 16 EXAMPLE 17 EXAMPLE 18 Dry resinS1001: 95 S1001: 80 S1001: 100 TAE200: 100 S1001: 95 S1001: 90 Ex. 4: 5Ex. 4: 20 (BA 7%) DOP: 5 DOP: 10 Tensile test Modulus of elasticity[MPa] 1940 840 2300 1780 2450 2250 Elongation at break [%] 129% 132%122% 136% 82% 127% Method B flow [cc/sec × 10E−2] 1.2 60.1 0.7Undetectable 2.1 7.6Ex. = EXAMPLE

INDUSTRIAL APPLICABILITY

According to the present invention, a polyvinyl chloride copolymer pasteresin having superior tensile properties in low-temperature workingconditions can be easily synthesized. A plastisol made from the resinhas superior gelation properties and storage stability.

1. A polyvinyl chloride copolymer resin for paste applications,comprising a copolymer of a vinyl chloride monomer and a macromonomerhaving a vinyl polymer main chain.
 2. The polyvinyl chloride copolymerresin according to claim 1, wherein the macromonomer having the vinylpolymer main chain comprises a monomer having at least one polymerizablegroup containing a polymerizable carbon-carbon double bond at an end ofthe monomer.
 3. The polyvinyl chloride copolymer resin according toclaim 1, wherein the macromonomer having the vinyl polymer main chain,the macromonomer having at least one polymerizable group containing apolymerizable carbon-carbon double bond at the end of the molecule, issynthesized by radical polymerization.
 4. The polyvinyl chloridecopolymer resin according to claim 1, wherein the polymerizable groupcontaining the polymerizable carbon-carbon double bond of themacromonomer having the vinyl polymer main chain has a structurerepresented by the general formula:—OC(O)C(R)═CH₂ (wherein R represents hydrogen or a C1-C20 organicgroup).
 5. The polyvinyl chloride copolymer resin according to claim 1,wherein R represents hydrogen or a methyl group.
 6. The polyvinylchloride copolymer resin according to claim 1, wherein the vinyl polymermain chain of the macromonomer is prepared by living radicalpolymerization.
 7. The polyvinyl chloride copolymer resin according toclaim 1, wherein the polymer main chain of the macromonomer is a(meth)acrylic polymer.
 8. The polyvinyl chloride copolymer resinaccording to claim 1, wherein the polymer main chain of the macromonomeris a (meth)acrylic ester polymer.
 9. The polyvinyl chloride copolymerresin according to, wherein the polymer main chain of the macromonomeris an acrylic ester polymer.
 10. The polyvinyl chloride copolymer resinaccording to claim 1, wherein the ratio (Mw/Mn) of the weight-averagemolecular weight (Mw) to the number-average molecular weight (Mn) of themacromonomer having the vinyl polymer main chain is less than 1.8. 11.The polyvinyl chloride copolymer resin according to claim 1, wherein theglass transition temperature of the macromonomer having the vinylpolymer main chain is −20° C. or less.
 12. The polyvinyl chloridecopolymer resin according to claim 1, wherein the copolymer contains 80to 99.95 percent by weight of the vinyl chloride monomer and 20 to 0.05percent by weight of the macromonomer having the vinyl polymer mainchain.
 13. A method for synthesizing the polyvinyl chloride copolymerresin according to claim 1, the method comprising polymerizing the vinylchloride monomer with the macromonomer having the vinyl polymer mainchain by aqueous polymerization.
 14. A method for synthesizing thepolyvinyl chloride copolymer resin according to claim 1, wherein thevinyl chloride monomer is polymerized with the macromonomer having thevinyl polymer main chain by at least one of emulsion polymerization,suspension polymerization, and microsuspension polymerization.
 15. Aplastisol composition exhibiting ready gelation and high storagestability, the plastisol composition comprising (A), (B), and (C): (A)100 parts by weight of a vinyl chloride polymer containing 20 to 100percent by weight of the polyvinyl chloride copolymer resin according toclaim 1 and 80 to 0 percent by weight of a vinyl chloride homopolymerresin; (B) 30 to 200 parts by weight of a plasticizer; and (C) 0 to 500parts by weight of a filler.
 16. The plastisol composition according toclaim 15, further comprising 0.1 to 10 parts by weight of a chemicalfoaming agent, wherein the plastisol is heated to form uniformmicro-cells, whereby the composition further exhibits excellent foamproperties.
 17. A resin for canvas and glove applications, prepared bydrying an aqueous dispersion mixture of 20 to 100 percent by weight ofthe polyvinyl chloride copolymer resin according to claim 1, and 80 to 0percent by weight of a vinyl chloride homopolymer resin.
 18. A polyvinylchloride rigid resin composition, comprising: 0.1 to 50 percent byweight of the polyvinyl chloride copolymer resin according to claim 1;and 99.9 to 50 percent by weight of a vinyl chloride homopolymer resin,whereby the processability is improved, and internal plasticization isachieved without a plasticizer.